It may be easier if you put the first earflap on another needle for now. With the RS of the flap on the needle facting you cast on stitches, then knit the sts that are still on the needle. Cast on more stitches, then knit the sts of the other earflap and cast on the remaining sts. You can use the cable cast on for all of these - at the end of the first flap, turn it to cast on the sts before you go to the other flap.
sue- knitting heretic